Mini recto problem — tube issue?

Hi Guys,

I recently noticed a loud low frequency hum that shows up within a few seconds of playing on my mini rectifier. It is present on the clean and pushed channels and the vintage channels — at 25 watts only. Switching to 10 watts eliminates it entirely and it doesn’t recur unless I switch back to 25 watt mode. It also sometimes disappears for a few seconds as I play then reappears. It is completely absent in the modern 25 watt mode. Thanks guys!

HB

Hi Hblu2002, I have a Mini Rec that has an identical noise problem to the one you have described and I have not been able to figure out how to remedy the problem. I can make the noise go away by switching between 10 and 25 watts, but the low-frequency noise always returns. Since you posted this a little over a year ago have you been able to diagnose what is causing this or any other update?
Thanks!